Composer has written a feature about musical work (6)
I believe the answer is:
chopin
'composer' is the definition.
(Frederic Chopin)
'feature about musical work' is the wordplay.
'feature' becomes 'chin' (facial feature).
'about' means one lot of letters goes inside another.
'musical work' becomes 'op' (abbreviation for opus).
'chin' placed around 'op' is 'CHOPIN'.
'has written a' acts as a link.
This may not be correct. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for chopin that I've seen before include "Polish pianist-composer" , "Composer of mainly piano works" , "popular composer" , "Polish composer who had affair with George Sand" , "Frederic . . . . . ., great Polish composer for piano" .)